This invention relates generally to intake air manifolds for internal combustion engines. More particularly, this invention relates to intake air manifolds integrating an exhaust gas recirculation (EGR) system for a diesel engine.
The use of exhaust gas recirculation (EGR) systems in internal combustion engines is well known. A typical EGR system takes a fraction of the exhaust gases from the exhaust manifold and injects it into the intake air for the engine where it is mixed with fresh air and fuel and then reburned. Mixing exhaust gases with fresh intake air and fuel lowers peak combustion temperatures thereby reducing formation rates of oxides of nitrogen in the exhaust gas. The use of an EGR system for the injection of exhaust gases into the intake air requires a plurality of separate components. The separate components can pose a problem since the space available in vehicle engine compartments is typically limited. Further, the additional components increase the complexity and time required to assemble the engine and can also increase the size of the engine.
Accordingly, there is a need for an intake air manifold integrated with an exhaust gas recirculation system.
The present invention provides an integrated intake manifold module that combines an intake air manifold with an exhaust gas recirculation (EGR) system, resulting in a novel and compact design that will optimize the limited space available in a vehicle engine compartment. The intake manifold module is comprised of an intake air manifold having an EGR valve aperture, an EGR cooler mounting, and an intake/EGR gas passage. There is also an EGR valve operatively mounted in the EGR valve aperture, and an EGR cooler cooperatively attached to the intake air manifold. The EGR cooler is between the intake air manifold and a top area of an engine block. Further, the EGR cooler comprises a gas outlet cooperatively attached to the intake/EGR gas passage, an exhaust gas inlet, a coolant inlet passage, a coolant outlet passage, and an EGR cooler mounting bracket cooperatively attached to the EGR cooler mounting. In operation, exhaust gases enter the EGR cooler through the EGR gas inlet. Coolant passes through the EGR cooler to cool the exhaust gases. The exhaust gases then pass through the EGR valve into the intake air manifold, where they mix with the intake air.
The intake manifold module advantageously integrates EGR system components, e.g., EGR valve, EGR gas outlet, and EGR coolant outlet, into the intake manifold via the use of casting cores without performance compromise. The intake manifold module has a compact design that reduces the number of fastening and sealing components (bolts, clamps, O-Rings, gaskets, etc). This minimizes the total number of components and sealing connections. This level of integration minimizes the assembly time and cost, and warranty costs while maintaining serviceability of the EGR valve and EGR cooler. In addition, this intake manifold module puts the EGR injection point in the intake manifold, closer to the engine cylinders. This improves engine performance by shortening the response and purge time of the system without impeding mixing and distribution of EGR gases in the manifold.
The following drawings and description set forth additional advantages and benefits of the invention. More advantages and benefits are obvious from the description and may be learned by practice of the invention.